The hypothesis was that an increase in serum lycopene levels following supplementation with capsules containing natural lycopene rich tomato extract would reduce oxidative stress and improve endothelial function in healthy men with low intake of fruits and vegetables. A randomized double-blind, placebo-controlled study was designed to assess the changes in serum lycopene levels, oxidative stress and endothelial function in response to an 8-week treatment with lycopene supplementation.